Autoxidation of thiols with cobalt (II) phthalocyanine-tetra-sodium sulfonate,attached to poly(vinylamine)

Summary The oxidation of 2-mercaptoethanol with molecular oxygen in water with cobalt(II)phthalocyanine-tetra-sodium sulfonate attached to poly(vinylamine) has been investigated.Specially attention was paid to the effect of pH and chain dimensions on polymer activity. The polymer catalyst possesses a large conformational freedom at neutral pH, but at higher pH a shrinkage of the polymer coil occurs and diffusion limitations cannot be excluded. The catalyst shows an enzyme-like behaviour in the autoxidation of thiol. Overall activation energies appear to decrease with increasing pH. At pH = 7.4, E_a = 61 KJ mole^–1; at pH = 9.5, E_a = 3 KJ mole^–1.Electrostatic effects are of major importance in the chemical reactivity since they affect the local thiol-anion concentration in the close vicinity of the polymer attached oxidation sites.     

Adsorption of copper(II), cobalt(II), and iron(III) ions from aqueous solutions on poly(ethylene terephthalate) fibers

The adsorption behavior of poly(ethylene terephthalate) (PET) fibers towards copper(II), cobalt(II), and iron(III) ions in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment time, temperature, pH of the solution, and metal ion concentration on the adsorption were investigated. Adsorption values for metal ion intake followed the following order: Co(II) > Cu(II) > Fe(III). One hour of adsorption time was found sufficient to reach adsorption equilibrium for all the ions. The rate of adsorption was found to decrease with the increase in the temperature. Langmuir adsorption isoterm curves were found to be significant for all the ions studied. The heat of adsorption values were calculated as −5, −2.8, and −3.6 kcal/mol for Cu(II), Co(II), and Fe(III) ions, respectively. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1935–1939, 1998     

Stability constants of adipate complexes of copper(II), nickel(II), zinc(II), cobalt(II), uranyl(II) and thorium(IV) determined by electrophoresis

Stability constants of Copper(II), Nickel(II), Cobalt(II), Zinc(II), Uranyl(II) and Thorium(IV) adipates have been determined by paper electrophoresis. Adipic acid (0.005 mol dm^?3) was added to the background electrolyte: 0.1 mol dm^?3 HClO₄. The proportions of (CH₂)₄COOH COO^? and (CH₂)₄C₂O⁼₂ were varied by changing the pH of the electrolyte. These anions yielded the complexes Zn(CH₂)₄COOH COO⁺, Co(CH₂)₄COOH COO⁺, Ni(CH₂)₄COOH COO⁺, Th(CH₂)₄COOH COO³⁺, Th[(CH₂)₄COOH COO]₄, Cu(CH₂)₄ C₂O₄ and UO₂[(CH₂)₄(C₂O₄)]^2?₂, whose stability constants are found to be 10^2.8, 10^2.8, 10^3.2, 10^5.2, 10^15.3, 10^2.7 and 10^11.8 respectively (μ = 0.1, temp. 40°C).     

Polymerization of 1,3-butadiene by bis(salicylaldiminate)cobalt(II) catalysts combined with organoaluminium cocatalysts

The one-pot reactions of salicylaldehyde or its derivatives with 2,6-dialkyl substituted anilines in the presence of metallating agent, Co(OAc)₂.4H₂O, yield a series of cobalt(II) complex precatalysts (Ar¹-NC-Ar²-O)₂Co (1, Ar¹ = 2,6-dimethylaryl, Ar² = aryl; 2, Ar¹ = 2,6-diethylaryl, Ar² = aryl; 3, Ar¹ = 2,6-diisopropylaryl, Ar² = aryl; 4, Ar¹ = 2,6-dimethylaryl, Ar² = 3-t-butylaryl; 5, Ar¹ = 2,6-diethylaryl, Ar² = 3-t-butylaryl; 6, Ar¹ = 2,6-diisopropylaryl, Ar² = 3-t-butylaryl) in high yields. The treatment of these cobalt(II) salicylaldimine complexes with ethylaluminum sesquichloride (EAS) forms highly active 1,3-butadiene (BD) polymerization catalysts, yielding polybutadienes of moderate molecular weights (MW = 33,900–44,500) with narrow molecular weight distributions (MWD = 1.29–2.36). All Co(II) complexes yield highly cis-1,4-polybutadienes (>94%) with negligible amounts of 1,4-trans (<2.32%) and 1,2-added (<3.37%) products in polymerizations at 30 °C combined with EAS. As the steric bulk at the cobalt center increases by changing the alkyl substituents on the ligand environment, 1,4-cis content decreases. The cis content and MW decrease as polymerization temperature increases. The polymerization yield and the cis content increase as BD concentration increases. The nonlinearity of [BD] to yield and [BD] to MW relationships demonstrates that the narrow MWD comes from uniform active species present in the polymerization system. The activation procedures of the Co(II) complexes in conjunction with EAS are studied by using UV-visible spectroscopy. Suitable correlations are found between polymerization activities and the changes in UV-visible absorption spectra of the complex.     

Surface grafting of poly(vinylamine) onto poly(ethylene) film by corona discharge‐induced grafting

Poly(vinylamine) (PVAm) was grafted on a poly(ethylene) (PE) film surface via the surface graft polymerization of N‐vinylformamide (NVF) and N‐vinylacetamide (NVA) and the subsequent hydrolysis of those grafted polymers. The surface was characterized by X‐ray photoelectron spectroscopy (XPS), contact angle, moisture absorption, and the leakage of electrostatic charge from the films. PNVF and PNVA were introduced onto the surface of the PE film successfully, in spite of the fact that the initiator for polymerization was a peroxide group. The grafted amounts of PNVF and PNVA were dependent on the grafting time. A PVAm‐grafted surface was obtained via the hydrolysis of the grafted PNVF. The grafted‐PNVA was not hydrolyzed under mild hydrolysis. The obtained PVAm‐grafted surface appeared to be useful for various applications, such as protein immobilization or chemical modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1583–1587, 1999     

Polymers containing metal chelate units. I. Immobilized mono- and binuclear chelates of nickel(II) and cobalt(II)

A number of polymer carriers with chelating groups such as diketones, diacylamines, and enaminoketones has been synthesized. The immobilized mono- and binuclear chelates have been prepared by the interaction of these polymeric ligands with nickel(II) and cobalt(II) acetates in alcohol. Spectral and magnetic data confirm the tetrahedral structure of the cobalt complexes and octahedral structure of the nickel complexes. The catalytic properties of the immobilized complexes in ethylene dimerization and butadiene polymerization have been investigated.     

Polychelates of poly(acrylic acid-co-acrylamide)with Cu(II), Co(II), and Ni(II) Synthesis and properties

SUMMARY Polychelates were obtained by addition of an aqueous solution of the poly(acrylic acid-co-acrylamide) to an aqueous solution of Cu(II), Co(II), and Ni(II). All the polychelates were insoluble in water and in common organic solvents. The polychelates were characterized by elemental analysis, FT-IR spectroscopy thermogravimetry, and showed tetrahedral arrangement for Co(II) and Ni(II). Magnetic and conductivity studies for all the polychelates were also carried out. The poly(acrylic acid-co-acrylamide) behaved as semiconductor. Received: 25 July 1997/Revised version: 1 December 1997/Accepted: 5 December 1997     

Pretreatment of cotton with poly(vinylamine chloride) for salt-free dyeing with reactive dyes

Poly(vinylamine chloride) has been investigated as a pretreatment for the salt-free dyeing of cotton with reactive dyes. Dye fixation was found to be much higher than by conventional dyeing without pretreatment, even in the presence of a large amount of salt. The influence of pretreatment conditions on dye fixation, such as pad–bake variables and the concentration of poly(vinylamine chloride), has been studied. The dyeing behaviour of CI Reactive Red 2 on pretreated cotton was examined and found to follow a Langmuir-type adsorption curve. Dyed cotton pretreated with poly(vinylamine chloride) showed excellent wash fastness and good rub fastness. It is concluded that poly(vinylamine chloride) is effective as a pretreatment for salt-free dyeing with reactive dyes.     

Synthesis, characterization, and properties of polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II)

SUMMARY Polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II) metal ions are synthesized. These compounds are characterized by FT IR, UV-vis spectroscopy, and thermal analysis. The electrical conductivity measurements are carried out. These demonstrate that at temperature close to 130°C the electrical conductivity increased to values near to the semiconductor range. The PM3 calculations are also carried to study the geometry of the polychelates. Received: 1 November 2000/Revised version: 20 March 2001/Accepted: 21 March 2001     

Compatibility of nylon 6 with poly(vinyl alcohol), hydroxylated poly(vinyl acetate) and poly(vinyl acetate)

Summary The compatibility of nylon 6 with poly(vinyl acetate)(PVAc) and poly(vinyl alcohol)(PVA) was investigated in terms of the melting-temperature depression. In order to vary the compatibility systematically, a hydroxylated poly(vinyl actate)(m-PVAc) was prepared by hydrolyzing PVAc with KOH in CH₃OH. It was found that the compatibility with nylon 6 is better in the systematic order PVA> m-PVAc> PVAc.     

Radiation crosslinking of poly(vinyl chloride) with trimethylolpropanetrimethacrylate. II. Dependence on radiation dose and blend composition

The radiation crosslinking of poly(vinyl chloride) (PVC) blended with trimethylolpropanetrimethacrylate (TMPTMA) has been examined. The polyfunctional TMPTMA undergoes polymerization incorporating the PVC into a 3-dimensional network. The kinetics and mechanisms of these crosslinking reactions were studied with particular reference to dependence on radiation dose and blend composition. The crosslinking rate was found to be proportional to the TMPTMA concentration. As the TMPTMA concentration decreased, soluble graft copolymers were produced in addition to insoluble networks. A gel permeation chromatography technique provided compositional information on the gel and sol fractions. The competition between polymerization, grafting, and degradation reactions was examined.     

Synthesis,characterization of poly(allylamine)chelates with Cu(II), Co(II) and Ni(II)

Summary The parent polymer, poly(allylamine) as ligand polymer was employed to synthesize polychelates of heavy metal ions. The functional poly(allylamine) and its Ni(II), Co(II) and Cu(II) metal chelates were characterized by elemental analysis, FT-IR spectroscopy, TGA, and SEM. For the polychelates magnetic and conductivimetry studies were also carried out.     

Separation/Preconcentration of Zn(II), Cu(II), and Cd(II) by Saccharomyces carlsbergensis Immobilized on Silica Gel 60 in Various Samples

Abstract

This study presents a solid phase extraction procedure based on column biosorption of Zn(II), Cu(II), and Cd(II) ions on Saccharomyces carlsbergensis immobilized on silica gel 60. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions for the quantitative recovery of the analytes, including pH, amount of solid‐phase, eluent type and flow rate of sample solution were examined. The effect of interfering ions on the recovery of the analytes was also investigated. Under the optimum conditions, recoveries of Zn(II), Cu(II), and Cd(II) were 99±2%, 98±2%, and 100±2% at 95% confidence level, respectively for spiked water samples. The analytical detection limits for Zn(II), Cu(II), and Cd(II) were 1.14, 1.66, and 1.48 ng mL^?1, respectively. The validation of the method was checked by the analysis of standard reference material (Tea leaves GBW‐07605) and spiked water, samples. The proposed method was applied for the determination of analytes in green onion, parsley, dam water, lake water, and tap water samples. The analytes has been determined in real samples with relative error lower than 8% and relative standard deviation lower than 10%.     

Polymer-metal complexes: Synthesis, characterization, and properties of poly(maleic acid) metal complexes with Cu(II), Co(II), Ni(II), and Zn(II)

SUMMARY Polymer metal complexes of poly(maleic acid) and Cu(II), Co(II), Ni(II), and Zn(II) were synthesized. Elemental analysis, as well as magnetic, spectral and thermal properties, in addition to electrical conductivities of the chelates were investigated, and possible structures have been assigned to the polychelates. Semi-empirical calculations at the PM3 level were carried out on the geometrical arrangement of the polychelates. Received: 19 November 1999/Revised version: 22 March 2000/Accepted: 31 March 2000     

Oxidation of mercaptans in light oil sweetening by cobalt(II) phthalocyanine–hydrotalcite catalysts

Three Mg–Al hydrotalcites containing cobalt(II) phthalocyanine were prepared by direct synthesis, anion exchange and structure reconstruction. Differences in physicochemical properties and mechanical resistance were observed. The results of the mercaptan oxidation reaction were compared to those obtained with an industrial non-basic impregnated active charcoal. An important activity difference in favor of the prepared catalysts was obtained, confirming that the adequate tuning of basic and oxidant properties lead to a promising catalyst.     

Electrophoretic studies of mixed ligand complexes in solution—copper(II), nickel(II), cobalt(II), uranyl(II) and thorium(IV)—tartarate—nitrilotriacetate

Paper electrophoresis has been used for the study of the equilibria in mixed ligand complex systems in solution. The method is based on the migration of a spot of a metal ion, with the complexants added in the background electrolyte (0.1 M perchloric acid), at a fixed pH. The concentration of one of the complexants [A] is kept constant, while that of second ligand [L] is varied. A graph of—log [L] against mobility is used to obtain information on the formation of the mixed ligand complex, and to calculate the stability constant. Using this technique, the values of overall stability constant of the complex metal—tartarate—nitrilotriacetate have been found to be 10^12.25, 10^5.98, 10^?3.56, and 10^3.74 for Cu(II), Ni(II), Co(II), UO₂(II) and Th(IV) complexes, respectively at μ = 0.1 and temp. = 40°C.     

Syntheses and characterization of a chelating resin containing ONNO donor quadridentate Schiff base and its coordination complexes with copper(II), nickel(II), cobalt(II), iron(III), zinc(II), cadmium(II), molybdenum(VI) and uranium(VI),

A new mixed Schiff base N,N′-ethylenemono(3-carboxysalicylideneimine)mono(salicylideneimine) has been synthesized by the condensation of equimolar quantities of ethylenediamine, salicylaldehyde and 3-formylsalicylic acid. A polymer supported Schiff base (PS–CH₂–LH₂) has been synthesized by the reaction of chloromethylated polystyrene (containing 3.9 mmol of chlorine per g of resin and 2% cross-linked with divinylbenzene) and the Schiff base N,N′-ethylenemono(3-carboxysalicylideneimine)mono(salicylideneimine). The polymer-anchored Schiff base reacts with metal salt/metal complex and forms polymer-anchored complexes having the formulae PS–CH₂–LCu, PS–CH₂–LNi, PS–CH₂–LCo, PS–CH₂–LFeCl·DMF, PS–CH₂–LZn, PS–CH₂–LCd, PS–CH₂–LMoO₂ and PS–CH₂–LUO₂. The polymer-anchored complexes have been characterized on the basis of elemental analysis, infrared and electronic spectra and magnetic susceptibility measurements. The shifts of the ν(CN) (azomethine) stretch to lower energy and ν(CO) (carboxylic) to higher energy in the polymer-anchored complexes indicate the ONNO donor behaviour of the chelating resin. The metal ions in the metal bound polymers can be leached by hot dilute formic acid, acetic acid or hydrochloric acid. The coordinated dimethylformamide is completely lost on heating the complexes in air. The complexes PS–CH₂–LCu and PS–CH₂–LCo are paramagnetic with square planar structure, PS–CH₂–LNi is diamagnetic with square planar structure and PS–CH₂–LFeCl·DMF is paramagnetic and octahedral, PS–CH₂–LZn and PS–CH₂–LCd are diamagnetic and tetrahedral, PS–CH₂–LMoO₂ and PS–CH₂–LUO₂ are diamagnetic and have octahedral structure. The stoichiometry and the structure of the metal bound polymers are comparable with those of metal complexes of N,N′-ethylenebis(salicylideneimine). This is the first report of the syntheses of a mixed Schiff base and its coordination complexes.     

Thermal characteristics of iron(III), cobalt(II), and copper(II) complexes of dipyridylamine anchored on polystyrene-divinylbenzene copolymer

Polystyrene-divinylbenzene (PS-DVB) (partially chloromethylated) has been modified by anchoring dipyridylamine (DPA) followed by subsequent complexation with Fe(III), Co(II), and Cu(II). Analytical and spectroscopic evidence has been presented to confirm the attachment of the metal-dipyridyl complex on the PS-DVB matrix. All the metal-loaded polymers exhibit appreciable improvement in thermal stability relative to the base polymer, the initial decomposition temperature and stability order being PS-DVB-DPA-Cu(315°C) > PS-DVB-DPA-Fe(II) (310°C) > PS-DVB-DPA-Co (300°C) > PS-DVB-DPA (280°C) = PS-DVB.DTA studies reveal exothermic peaks between 300 and 380°C, 420 and 440°C, and 500 and 700°C, which are ascribable to the exothermic cleavage of the PS-DVB-DPA matrix. The glass transition temperatures of the modified polymers do not reveal any characteristic difference from the corresponding value for the base polymer. © 1993 John Wiley & Sons, Inc.